An electric motor having a commutator and brushes usually includes a filter circuit connected between the brushes and the external power source, to reduce electrical noise or EMI. The filter circuit usually has an inductor. During operation, the commutator rotates at a high speed with respect to the brushes and the current in windings connected to the commutator changes rapidly, producing EMI signals. These signals couple with the inductor. When the EMI signals are of high frequency, the inductor will perform as an antenna to emit high frequency interference signals, leading to failure in the EMI test of the motor.
Accordingly, there is a desire for a new motor having a filter circuit including an inductor and which emits low levels of EMI signals.